Art of rolling tubes.



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N.-'7z1,zo9. PATENTED EEB. 24, 190,3. M. MANNESMANN. ART 0EROLLINGTUBES.

AEELIOA'TION FILED 001. 7, 1901. BENEWED SEPT. 17, 1902.

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Tubes.

PATBNTED FEB. 24, 1903.

M. MANNESMANN. ART 0F ROLLING TUBES. APPLIOATION FILED 00121, 190i.'BHNBWBD SEPT. 17, 1902.

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UNITED STATES PATENT OFFICE.

ART OF ROLLING TUBES.

SPECIFICATION forming part of Letters Patent No. 721,209, dated February24, 1903. Application iiled October 7, 1901. Renewed September 17, 1902.Serial No. 124,805. (No model.)

l'o all Loh/ont it' inlay concern:

Be it known that I, MAX MANNESMANN, a citizen of the Empire of Germany,residing at Remscheid-Bliedinghausen, Germany, have invented new anduseful Improvements in the Art of Rolling Tubes, of which the followingis a specification.

My invention relates to the rolling out of hollow billets or blanksbetween grooved rolls on a mandrel into a tube.

In rolling out tubes from a'hollow blank or billet the blank washeretofore subjected on a mandrel to the-pressure of two rolls, whichfirst contacted with or compressed the material at diametricallyopposite points near the middle ot' the groove,so as to stretch theblank in longitudinal direction. At the same time those parts ot' the`circumference of the tube near the edges of the groove and which werenot under compression by the rolls were stretched by the cohesion withthe compressed and elongated parts. The tube was then turned around itsaxis through an angle of ninety degrees and subjected a second time tothe rolling operation, so that those portions which were elongatedwithout heilig compressed were compressed and rolled out and thepreviously-com pressed portions were elongated without being compressed.This process subjected the tube to tearing strains alternating withcompression, and several passes were required for producing the iinishedtube. In rolling out hollow blanks on a mandrel between three or fon rgroovcd rolls the same operation was performed. The caliber of the rollswas cut away tanggfentially to the grooves, so that the center portionof the grooves first touched the blank, and room was left at the sidesof the grooves to prevent the formation of fins of the blank. The blankpassed many times through the rolls, turned around its axis between eachtwo passes for sixty degrees with three rolls and forty-five degreeswith four rolls, and so rolled out to the desired degree, whereby thecircumference of the blank at three or four points was alternatelysubjected to a strong pressure by the center portions of the grooves andto tearing strains or a crowding up between the cut-away sides of thegrooves.

The object of the present invention is to overcome the defects of thisprocess, avoiding the alternating compression and tearing strains, andfurnishl a process in which the stretching of the blank into a tube isproduced undel pressure throughout its oros..- section, so that thestretching operation is produced under pressure exerted on the entirecircumference of the tube, and a blank can be rolled out into a tube inone pass through the rolls; and the invention consists of theimprovement in the art of rolling tubes by subjecting a hollow blank orbillet of a size larger than the pass on a mandrel through its entirecross-section to the pressure of posi;-

tively-driven rolls, which first contact with or compress the metal nearthe edges ofthe groove, so as to squeeze down somel of the material ofthe blank and intentionally to produce ridges, iins, orribs and astretching of the whole body of the blank, as vwell as of the ridges,tins, or ribs, in longitudinal direction.

The invention consists, further, of additional stcps in the art ofrolling tubes, which will be fully described hereinafter and thenpointed out more specifically in the claims.

In the accompanying drawings, Figure 1 represents a vertical transversesection of a tube and mandrel subjected to the pressure of rolls by theprocess heretofore used. Figs. 2, 4, 6, 8, and 10 are verticallongitudinal sections illustrating the successive steps of my improvedprocess of rolling tubes by circumferential pressure on the hollow blankor billet. Figs. 3, 5, 7, 9, and l1 are vertical transverse sectionsrespectively on lines 3 3, Fig. 2, 5 5, Fig. 4, 7 7, Fig. 6, 9 9, Fig.S, and 11 11, Fig. 10. Fig. 12 is aside view of atnbe shown partlyrolled out by my improved process. Figs. 13 and 14 are verticaltransverse sections respectively on lines 13 13 and 14 14, Fig. 12.

Fig. 15 is a side elevation of a linie-hed tube, on which the ribs' orfeathers formed on the exterior of the tube are partly Figs. 16 and 17trimmed off at their edges.

are vertical transverse sections respectively on lines 16 16 and 17 17,Fig. 15. 19and 20 are end views of a three-roll rolling-mill forcarrying out my improved proc- Figs. 18,

ess. Fig. 21 is a side elevation, partly in section, showing the cuttersfor cutting off the f exterior ribs or feathers, and Figs. 22 and 23 arevertical transverse sections respectively on lines 22 and 23 in Fig. 2l.

Similar letters of reference indicate corresponding parts.

In the drawings, m represents the mandrel over which the hollow blank orbillet is rolled out.

bis the blank,and c ando' the rolls employed for rolling out the blankon the mandrel. Positive rotary motion is imparted to the shafts of the`rolls in any suitable manner. The rolls are so disposed around themandrel that'pressu re nearly around its entire circumference is exertedon the hollow blank or billet during the rolling operation, four rollsbeing preferably used for this purpose, the edges of which are arrangedclosely together, as shown in Fig. ll, so that the tube is formed inclose contact with the mandrel around the entire circumference of thesame,while in the small spaces between the rolls small ribs or feathersr are formed on the outside of the tube. As the rolling operationprogresses and the blank is forced through the rolls the spaces notunder pressure at the entry of the pass diminish as the working faces ofthe rolls approach each other, whereby some of the material of the blankwhich is located between and acted upon by the beveled parts outside ofthe edges of the rolls is compressed and elongated with the body of thetube, so as to form longitudinal ribs on the outside of the same. Theentire circumference of the tube, as well as the ribs or feathers formedthereon, is in such way under compression while being rolled. Therolling operation is best performed by means of four rolls, astheysurround the entire circumference of the blank in a greater or moreperfect degree than three or only two rolls, as will read' y appear froman inspection of Figs. 4 to 1l, in which fou r rolls, and of Figs. 18and 19, in which three rolls, are used. The longitudinal ribs orfeathers rr', formed at the exterior circumference of the tube, afterthe same is rolled out can either be removed by a separate cuttingoperation or immediately as the tube leaves t-he rolls by acutting-toolf, which is arranged in proximity to the outgoing end of therolls, as shown in Fig. 20, or the edges of the ribs or feathers may betrimmed olf and the remaining portions of the ribs or ridges retained onthe tube, as shown in Fig. 15. In case, however, tubes with exteriorribs are to be rolled, such as are used for the masts of electric lightsor the poles of overhead electric railways, then the circumference ofthe rolls may be so shaped that rounded-off ribs are formed, which actthen in the nature of reinforcing-ribs that are not required to beremoved from the tube. In this case the ribs should be made of uniformthickness throughont. The ribs or feathers 1 may also be formed by thecorrespondingly-beveled or 'at any desired angle cut-away parts of therolls outside cf their edges in dovetail shape or undercut, as shown iuFig. 19, or the rims outside of the edges of the grooves may entirely bedispensed with, asshown in Fig. 20.- In this case the shaped edges ofthe rolls squeeze 0E or cut olf a portion of the material of the blank.Even without the circumferential rims the whole cross-section of theblank is compressed to some extent, as the edges of the rolls crowd upthe material cut 0E by them from the blank. This crowding up becomeslarger when instead of sharp edges rounded-olf edges are employed; butcircumferential rims to compress the ribs, feathers, or fins formed bythe edges of the rolls. are preferred. Y

When a cutting-tool is usedA for cuttingo' the ribs during the rollingof the tube, a guidebox cl is used for conducting off each cut-oh? rib,so that the same does not interfere with the rolls and theroller-bearings. This cutting o of the ribs can be accomplished in amore or less perfect manner and the slight unevenness remaining on thetube be evened up by grinding or polishing or by rolling them down, sothat a perfectly smooth exterior surface is obtained.

I am aware that heretofore the attempt was made to form longitudinalribs on tubes by a drawing process. Such tubes, however, have after thedrawing process a considerably inferior rate of elongation orcontraction than tubes produced by my rolling process betweenpositively-driven rolls. Besides that, only very ductile material can bestrongly stretched out by a drawing process, while many materials can berolled out by means of positively-driven rolls, which are unfit to thedrawing process, as in rolling the stretching out takes place undercompression.

The edges of the rolls in my rolling process lirst impinge upon thehollow blank, compress the same, squeeze down a certain portion of thematerial of the same, and form ribs, ridges, fins, or feathers betweenthem while holding the rolled-out tube under compression around thewhole circumference of the mandrel. Hitherto in rolling out metals finswere sought to be avoided, as the blanks had to pass many times throughthe rolls, and tins produced by one pass would spoil IOO IIO

the tube when being turned for ninety degrees and passed again throughthe rolls. In my new rolling process Iproduce fins, ribs,ridges, orfeathers intentionally. I compress the hollow blank strongly between therolls and the mandrel, stretch out the blank into a tube in one pass,and form fins, ribs, or feathers, so that the tube cannot be turned forninety degrees and again passed through the rolls; but I stretch ont theblank into a tube in one pass, so that a turning of the tube for ninetydegrees and asecond pass through the rolls is unnecessary. Such ribs,fins, or feathers may remain on the finished tube Vor be cut olf.

I am aware that in welding tubes between two rolls fins are sometimesproduced at the E view-"wam", ...M.-...... ..4 m

tween the well-known .welding-rolls. simnl taneouslywith the weldingoperation, the.

seam would be opened and the welding of the seam prevented. By saidfirst im pingementof. the rolls at their edges on the blank the same isfirst compressed near those points of-,the circumference which at the.entry of the roll-v pass are not embraced by the rolls. By the use ofthree or fou-r rolls forming the caliber: these three parts of thecircumference ofthe blank between the edges of the lvrolls at the entr-yto the roll-pass are smaller than with two rolls, and therefore embracethe hollow in` a more perfect manner.. Such rolls the e'dges of whichrst impingefon the blank will in most cases move the material of theblank near the edges inwardlyfv close to the mandrel before the groovedcenter portions of the rolls compress the othenparts of thecircumference of the blank. During rolling the adjacent edges oftherolls approach each other and finally come close together, com.

pressing between them ns, ribs, or feathers formed on the tube, so thatthe whole crosssection of the tube is under enormous compression by therolls. This enormous compression of the whole crosssection of the blankproduces a flow of its material in longitudinal direction and thestretching out of the same. When the thickness of the fins is made verysmall and smaller than the thickness of the wall in the rolled-out tube,then in many cases the pressure between the rims of the rolls being incontact with said fins may be greater than the pressure between thegrooved parts of the rolls and the mandrel. As the material of the blankcannot flow out of a room with smaller pressure into a room being underhigher pressure, the escape of material of the tube between the groovedparts of the rolls and the mandrel under such condition is eifectivelyprevented. The fins hereby filling out the free spaces between the edgesof the caliber act in a similar way as hard pieces of metal would do-i.e., they complete the caliber formed between the rolls and produce anopening or caliber between the rolls closed at its entire circumference.The feathers or ns, therefore, being intentionally produced andcompressed between the rims of the rolls, are means to aid the action ofthe rolls and the mandrel in rolling outa hollow blank into a tube inone pass.

Instead of rolling out a hollow vbillet or blank in one pass through therolling-mill, as described, I may pass the blank several times throughthe mill; but in this case the blank, with its fins or feathers, must befed in such way to the mill that each .iin or feather is 'in a planelaid through the axis of the blank and the space between two adjacentedges of the rolls. In such way by the second pass the height of the iinor feather will be increased; or in producing tubes from hollow billetsor blanks by severalpasses the fins or feathers produced between therolls may be cut olf and then the tube again be passed through therolls. A tube so stretched out by several passes is similar to andtheequivalent of a tube stretched out to the's'aine extent by one pass, thedierence being only in theiheight or form'of the fins or feathers. Theabove-described process is' especially useful for producing or rollingout seamless tubes; but all other kinds of tubes or hollowI blanks maybe rolled out bysaid rolling process.

Having thus described my invention, vI

claim and desire to secure by Letters Patent- 1. The improvement in theart of rolling tubes, which consists in subjecting the hollow blank orbillet of a size larger than the pass on a mandrel to the pressure ofposi tively-driven rolls, which Iirst contact with,

or compressthemetal near the edges of the groove, so as to stretch it inlongitudinal direction into a tube, and to compress the same around theentire circumference of the mandrel, substantially as set forth. g

2. The improvement in the art of rolling tubes, which consists insubjecting the entire cross-section of, a hollow blank or billet of asize larger than the pass, on a mandrel to the action ofpositively-driven rolls, which rst contact with, or compress, vthe metalnear the edges of the groove, so as to stretch itin longitudinaldirection into a tube, and 'to com press the same around its entirecircumference, substantially as set forth.

3. The improvement in the art of rolling tubes, which consists insubjecting the blank to the reducing action of positively-driven rollson a mandrel, simultaneously with the squeezing action of the edges ofthe rolls, whereby a relatively large reduction of the blank and astretching of the same in a longitudinal direction into a tube withlongitudinal ribs, ridges, fins or feathers is produced, substantiallyasdescribed.

4. The improvement in the art of rolling tubes, which consists insubjecting the entire cross-section'of a hollow blank or billet of asize larger than the pass on a mandrel to the action ofpositively-driven rolls, which rst contact with or compress, the metalnear the edges of the groove, so as to stretch the same in longitudinaldirection, and forming simultaneously exterior longitudinal ribs, finsor ridges, at the circumference of the tube at the points between theedges of the rolls, substantially as set forth.

5. The improvement in the art of rolling tubes, which consists insubjecting a hollow billet or blank of a size larger than the rollpasson a mandrel to the pressure of three or more 4positively-driven rolls,which first contact with or compress the metal near the edges IOO IIO

of the groove so as to stretch the same in longitudinal direction, andforming simultaneously exterior longitudinal ribs, fins or ridges at thecircumference of the tube at4 the points between the edges of the rolls,substantially as set forth.

6. The improvement in the art of rolling tubes, which consists insubjecting a hollow blank or billet of a size larger than the rollpass,on a mandrel, to the pressure of three or more positively-driven rolls,which first contact with, or compress, the metal near the edges of thegroove, and forming simultaneously exteriorlongitudinal ribs, fins,feathers or ridges at the circumference of the blank, and stretching outthe ribs, fins, feathers or ridges simultaneously with the other part ofthe blank in longitudinal direction, substantially as set forth.

7. The improvement in the art ofrolling tubes, which consists insubjecting a hollow blank or billet of a size larger than the pass on amandrel to the pressure of three or more positively driven rolls whichfirst contact with, or compress, the metal near the edges of the groove,forming simultaneously exterior longitudinal ribs, fins, feathers orridges at the circumference of the tube, and at points between the edgesof the rolls, stretching out in longitudinal direction said fins, ribs,feathers or ridges simultaneously with the other parts of the blank, andthen trimming olf the outer edges of the fins, ribs, feathers or ridges,substantially as set forth.

8. The improvement in the art of rolling tubes, which consists insubjecting a hollow billet or blank of a size larger than the pass, on amandrel, to the pressure of three or more positivelydriven rolls whichfirst contact with, or compress, the metal near the edges of the groove,stretching out the blank into a tube, forming, and stretching outsimultaneously in longitudinal direction ribs, fins, feathers or ridgesat the circumference of the tube at points between lthe edges of therolls,

and then cutting 0E the exterior ribs, fins, feathers or ridges formed,substantially as set forth.

9. The improvement in the art of rolling tubes, whichv consists insubjecting the entire cross-section of a hollow billet or blank of asize larger than the pass, on a mandel, to the action of three or morepositively-driven rolls which first contact with, or compress, the metalnear the edges of the groove so as to stretch the same in longitudinaldirection, forming, and stretching out simultaneously in longitudinaldirection, exterior longitudinal ribs, fins or ridges at thecircumference of the tube and at points between the edges of the rolls,and then cutting off the exterior ribs, ns or ridges formed,substantially as set forth.

10. The improvement in the art of rolling tubes, which" consists insubjecting the entire cross-section of a seamless hollow billet or blankof a size larger than the roll-pass, on a mandrel, to the action ofthree or more positivelydriven rolls, which first contact with orcompress, the metal near the edges of the groove, forming ribs, fins,ridges or feathers on the circumference of the blank, at points betweenthe edges of the rolls, and stretching out the hollow part of the blank,and the ribs, ns, ridges or feathers in longitudinal direction, andcutting off said ribs, ns, ridges or feat-hers, substantially as setforth.

11. The improvement in the art of rolling seamless tubes, which consistsin subjecting the entire circumference of the tube of a size larger'.than the pass, on a mandrel, to the pressure of. three or morepositively-driven rolls which lrst contact with, or compress, the metalnear the edges of the groove, so as to stretch the blank longitudinally,forming simultaneously, and stretching out in longitudinal direction,exterior longitudinal ribs, finsor ridges at the circumference of thetube at the points between the edges of the rolls, and then cutting offthe exterior ribs or ridges thus formed, 4and finally smoothing andiinishing olf the exterior surface of the tube thus obtained,substantially as set forth.

In testimony whereof I aliix my signature in presence of two witnesses.

, MAX MANNESMANN.

Witnesses:

ARCHER PETER, EMORY H. BOGLEY.

